Ventricular tachyarrhythmia (VTA) refers to a variety of medical conditions characterized by an abnormally elevated heart rate. When the heart beats excessively rapidly, the heart pumps less efficiently, and provides less blood flow to the rest of the body. The increased heart rate also leads to increased work and oxygen demand by the heart, which can lead to rate-related ischemia. Ventricular tachyarrhythmia events are related to sudden deaths, especially in patients with severe heart disease. Examples of ventricular tachyarrhythmia events include ventricular tachycardia, ventricular fibrillation, and ventricular flutter. Subjects diagnosed as having ventricular tachyarrhythmia often receive an implantable cardiac device, e.g., a cardiac defibrillator (ICD) or cardiac resynchronization treatment (CRT) device, or a combination ICD-CRT (CRT-D) device. Some subjects having ventricular tachyarrhythmia that receive such a device demonstrate reduced morbidity and mortality (Scott et al., Europace. 13(10):1419-27 (2011)). Some patients diagnosed with heart failure and receiving standard pharmacological therapy develop worsening disease, whereby such pharmacological therapy is no longer sufficient, and device therapy (e.g., ICD, CRT, or CRT-D device) becomes necessary to preserve these patients' lives. Existing guidelines for selecting treatment including an implanted cardiac device (see, e.g., Epstein et al., Circulation. 117:e350-e408 (2008)) are unable to predict which subjects will benefit most from device therapy.